Chapter 27 // Exercise 16 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022 and ISO C11 Standard.

Chapter 27 // Exercise 16

Use macros to obscure (simplify the notation for) the implementation in the previous exercise.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%2016.c

Of course the final exercise had to be creating some disgusting macros. And with that

I can't believe that was the final exercise. It's been 7 years. I bought this book back in January 2016 with no knowledge of programming (apart from some brief HTML back in '98) and now I've been programming in C++ for 7 years, 4 and half of them professionally; I get paid to make video games, it's crazy.

I'm going to spend a bit of time collecting my thoughts and then come back with a full review of the book. I think my title is going to be "Why you should learn C++ as your first language". I honestly don't think I would've wanted to learn C++ any other way now.

I've been feeling a bit nostalgic lately and going back over books I bought way back in 2016 and 2017 as well as reading my green text on the early exercises of P&P posted on here. I read a chapter 4 post and the memories of that night came flooding back to me. It took me 6 hours to write a function comparing the size of two ints. It was 3am and I was so frustrated I started crying. I developed a fear of bools. Its absolutely hilarious to me now as I sit here reading a random book, silently ripping apart the authors code because they stored an pointer to an enum.

My mantra at work is "git gud". I can relax a bit when I've "gitten gud", then I can "git gudder". I honestly believed I hadn't really changed at all but lately I've started to realise that I can "just do stuff now". 6 years ago I bought Programming Game AI by Example by Mat Buckland. I tried to read it and follow along with the code but it went completely over my head as I had no experience with inheritance and I was convinced OOP was evil (because I didn't want to understand it). Recently, I picked the book back up and not only implemented the code from snippets with no problem but changed it as I was going along, grumbling about the authors use of singletons and lack of interfaces.

2 years ago I read the online book Ray Tracing in one Weekend and attempted to multi-thread it. It was a disaster and no matter how many times I read MSDN or StackOverflow I just couldn't get my attempts to work. Earlier this year I had another go and got a hacky version working in an afternoon. It's not perfect but it worked and I just "knew" how to do it.

3 months after starting as an intern at Rare, I asked a senior in a catch-up "when do you stop feeling like shit?" and his response was "you don't, but over time it won't be as bad". I pressed him for an actual time for "over time" and he just laughed and said "3 years". It's been 4 years since I asked him that.

It took me a very long time to stop feeling like a waitress/receptionist and start thinking of myself as a programmer. 

Thank you Bjarne for giving me the tools to change my life. 

Chapter 27 // Exercise 15 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022 and ISO C11 Standard.

Chapter 27 // Exercise 15

Simulate single inheritance in C. let each "base class" contain a pointer to an array of pointers to functions (to simulate virtual functions as freestanding functions taking a pointer to a "base class" object as their first argument); see section 27.2.3. Implement "derivation" by making the "base class" the type of the first member of the derived class. For each class, initialise the array of "virtual functions" appropriately. To test the ideas, implement a version of "the old shape example" with the base and derived draw() just printing out the name of their class. Use only language features and library facilities available in standard C.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%2015.c

Jesus christ, I had to get ChatGPT in for this one because I had no idea how start. What a load of faffing about. I used to think inheritance in C++ was confusing, well get a load of inheritance in C! It all kind of seems a bit pointless in C. 

I didn't go too far into this exercise, literally just creating the draw() functions for a shape and a circle. Shape can also be created, it's not abstract.

Chapter 27 // Exercise 14 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022 and ISO C11 Standard.

Chapter 27 // Exercise 14

Write a function that takes an array of ints as its input and finds the smallest and the largest elements. It should also compute the median and mean. Use a struct holding the results as the return value.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%2014.c

Ah finally, a nicer "easy" one. This reminded me a lot of the exercises we did way back in chapter 4. God, that feels like a lifetime ago.

Chapter 27 // Exercise 13 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022 and ISO C11 Standard.

Chapter 27 // Exercise 13

Write a program that does the equivalent of strings; cin >> s; in C; that is, define an input operation that reads an arbitrarily long sequence of whitespace-terminated characters into a zero-terminated array of chars.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%2013.c

I was a bit confused on this one as cin stop reading in characters when it encounters whitespace; have to use getline() to include the whitespace. So with the statement "define an input operation that reads an arbitrarily long sequence of whitespace-terminated characters" I decided instead he meant more of a getline() so we include whitespace characters. So if you were to type "this is a sentence", it captures the entire sentence and prints "this is a sentence". Maybe that's not what he meant though.

Chapter 27 // Exercise 12 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022 and ISO C11 Standard.

Chapter 27 // Exercise 12

Implement a (C-Style string, int) lookup table with operations such as find(struct table*, const char*), insert(struct table*, const char*, int) and remove(struct table*, const char*). The representation of the table could be and array of a struct pair or pair of arrays (const char*[] and int*); you choose. Also choose return types for your functions. Document your design decisions.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%2012.c

I originally did a really simple hash function however ended up with collision in the table quickly. I did some searching around and came across the terms "linear probing" where we keep going through slots to find a new one, wrapping round to beginning if needed.

The implementation isn't perfect but it'll do. For my design decisions:

Representation: I chose an array of struct pairs because it keeps the key-value pairs together, which makes it more intuitive.

Return Types: For find(), I return the int value associated with the key. If the key isn't found, I' return a special value, like -1.

For insert(), I return 0 if the insertion was successful and -1 if not (for example, if the table is full).
For remove(), I return 0 if the key was successfully removed and -1 if the key was not found.

Handling Collisions: For simplicity, I handled simple collisions only. This means the table has a fixed size, and if it's full, you can't insert more items.

Capacity: The table has a fixed size, which for this example, is set to 100. it will wrap round to find free slots but after that it won't insert any more.